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<html>
<head>
	<meta http-equiv="Content-type" content="text/html; charset=utf-8"/>
	<title>参考对照学习</title>
	 <script src="core.js"></script>
	 <script src="sizzle.js"></script>
	 <script src="other.js"></script>
</head>
<body>


<ul class="level-1">
  <li class="item-i">I</li>
  <li class="item-ii">II
    <ul class="level-2">
      <li class="item-a">A</li>
      <li class="item-b">B
        <ul class="level-3">
          <li class="item-1">1</li>
          <li class="item-2">2</li>
          <li class="item-3">3</li>
        </ul>
      </li>
      <li class="item-c">C</li>
    </ul>
  </li>
  <li class="item-iii">III</li>
</ul>

<script type="text/javascript">

var li = $('.item-ii');


function find(elem, selector) {
  return elem.querySelectorAll(selector);
}



console.log(find(li[0] ,'li'))
//console.log( li.find('li')  )



function sibling(n, elem) {
  var matched = [];
  for (; n; n = n.nextSibling) { //如果存在下一个兄弟节点
    if (n.nodeType === 1 && n !== elem) { //是元素节点，且不是当前选择器元素
      matched.push(n);
    }
  }
  return matched;
}

var ul = document.querySelectorAll('.level-2')[0];



</script>

</body>
</html>